#!/usr/bin/env python """ Transmit N simultaneous narrow band FM signals. They will be centered at the frequency specified on the command line, and will spaced at 25kHz steps from there. The program opens N files with names audio-N.dat where N is in [0,7]. These files should contain floating point audio samples in the range [-1,1] sampled at 32kS/sec. You can create files like this using audio_to_file.py """ from gnuradio import gr, eng_notation from gnuradio import usrp from gnuradio import audio from gnuradio import blks from gnuradio.eng_option import eng_option from optparse import OptionParser import usrp_dbid import math import sys from gnuradio.wxgui import stdgui, fftsink from gnuradio import tx_debug_gui import wx ######################################################## # instantiate one transmit chain for each call class pipeline(gr.hier_block): def __init__(self, fg, filename, lo_freq, audio_rate, if_rate): src = gr.file_source (gr.sizeof_float, filename, True) fmtx = blks.nbfm_tx (fg, audio_rate, if_rate, max_dev=5e3, tau=75e-6) # Local oscillator lo = gr.sig_source_c (if_rate, # sample rate gr.GR_SIN_WAVE, # waveform type lo_freq, #frequency 1.0, # amplitude 0) # DC Offset mixer = gr.multiply_cc () fg.connect (src, fmtx, (mixer, 0)) fg.connect (lo, (mixer, 1)) gr.hier_block.__init__(self, fg, src, mixer) class fm_tx_graph (stdgui.gui_flow_graph): def __init__(self, frame, panel, vbox, argv): MAX_CHANNELS = 7 stdgui.gui_flow_graph.__init__ (self, frame, panel, vbox, argv) parser = OptionParser (option_class=eng_option) parser.add_option("-T", "--tx-subdev-spec", type="subdev", default=None, help="select USRP Tx side A or B") parser.add_option("-f", "--freq", type="eng_float", default=None, help="set Tx frequency to FREQ [required]", metavar="FREQ") parser.add_option("-n", "--nchannels", type="int", default=4, help="number of Tx channels [1,4]") parser.add_option("","--debug", action="store_true", default=False, help="Launch Tx debugger") (options, args) = parser.parse_args () if len(args) != 0: parser.print_help() sys.exit(1) if options.nchannels < 1 or options.nchannels > MAX_CHANNELS: sys.stderr.write ("fm_tx4: nchannels out of range. Must be in [1,%d]\n" % MAX_CHANNELS) sys.exit(1) if options.freq is None: sys.stderr.write("fm_tx4: must specify frequency with -f FREQ\n") parser.print_help() sys.exit(1) # ---------------------------------------------------------------- # Set up constants and parameters self.u = usrp.sink_c () # the USRP sink (consumes samples) self.dac_rate = self.u.dac_rate() # 128 MS/s self.usrp_interp = 400 self.u.set_interp_rate(self.usrp_interp) self.usrp_rate = self.dac_rate / self.usrp_interp # 320 kS/s self.sw_interp = 10 self.audio_rate = self.usrp_rate / self.sw_interp # 32 kS/s # determine the daughterboard subdevice we're using if options.tx_subdev_spec is None: options.tx_subdev_spec = usrp.pick_tx_subdevice(self.u) m = usrp.determine_tx_mux_value(self.u, options.tx_subdev_spec) #print "mux = %#04x" % (m,) self.u.set_mux(m) self.subdev = usrp.selected_subdev(self.u, options.tx_subdev_spec) print "Using TX d'board %s" % (self.subdev.side_and_name(),) self.subdev.set_gain(self.subdev.gain_range()[1]) # set max Tx gain self.set_freq(options.freq) self.subdev.set_enable(True) # enable transmitter sum = gr.add_cc () # Instantiate N NBFM channels step = 25e3 offset = (0 * step, 1 * step, -1 * step, 2 * step, -2 * step, 3 * step, -3 * step) for i in range (options.nchannels): t = pipeline (self, "audio-%d.dat" % (i % 4), offset[i], self.audio_rate, self.usrp_rate) self.connect (t, (sum, i)) gain = gr.multiply_const_cc (4000.0 / options.nchannels) # connect it all self.connect (sum, gain) self.connect (gain, self.u) # plot an FFT to verify we are sending what we want if 1: post_mod = fftsink.fft_sink_c(self, panel, title="Post Modulation", fft_size=512, sample_rate=self.usrp_rate, y_per_div=20, ref_level=40) self.connect (sum, post_mod) vbox.Add (post_mod.win, 1, wx.EXPAND) if options.debug: self.debugger = tx_debug_gui.tx_debug_gui(self.subdev) self.debugger.Show(True) def set_freq(self, target_freq): """ Set the center frequency we're interested in. @param target_freq: frequency in Hz @rypte: bool Tuning is a two step process. First we ask the front-end to tune as close to the desired frequency as it can. Then we use the result of that operation and our target_frequency to determine the value for the digital up converter. Finally, we feed any residual_freq to the s/w freq translater. """ r = self.u.tune(self.subdev._which, self.subdev, target_freq) if r: print "r.baseband_freq =", eng_notation.num_to_str(r.baseband_freq) print "r.dxc_freq =", eng_notation.num_to_str(r.dxc_freq) print "r.residual_freq =", eng_notation.num_to_str(r.residual_freq) print "r.inverted =", r.inverted # Could use residual_freq in s/w freq translator return True return False def main (): app = stdgui.stdapp (fm_tx_graph, "Multichannel FM Tx") app.MainLoop () if __name__ == '__main__': main ()